A gunman was killed during an assault against a police station while four policemen were injured in a separate attack against their patrol in eastern Saudi Arabia, home to the Shiite majority, it was reported Saturday. "Four masked men entered with their motorcycles to the police station in al-Awamiya where one of them threw a Molotov cocktail while the others opened fire on the building," said the spokesman of the Ministry of Interior, Mansour al-Turki, who was quoted by the official SPA news agency. "The guards returned fire, killing one assailant while his companions were able to flee," he said.

The attack, which occurred in the Shiite city of al-Awamiya, occurred Friday night, less than a week after the death of two Shiite demonstrators in clashes with police in the district of Qatif (east of the kingdom), following the arrest of a Shiite cleric, Sheikh Nimr Baqer Al-Nimr, known for his harsh criticism of the Sunni authorities.

Mr. Turki warned that police would not tolerate "the rioters, especially those who are armed," and would act against those who support them.

For their part, 37 Shiite clerics issued a statement in which they attributed the tensions in the east to "the policy of religious discrimination that the government and official religious authorities have implemented for decades."

At the same time, they urged the youth to "stay away from violence" and "not respond to those trying to provoke you and drive you to violence to label your movement as a terrorist." They also called on the authorities to "release political activists (...) including Sheikh Nimr al-Nimr."

In a separate statement released by SPA, the spokesman for the Interior Ministry said that on Friday night "two patrols of the security forces came under fire from gunmen on motorcycles in the city of Saihat ", noting four members of law enforcement were wounded.

The eastern of Saudi Arabia, an oil-rich region where the majority of residents include two million Shiites, has been rocked by sporadic unrest since March 2011. The unrest turned violent from the fall of 2011, as nine people have been killed since.

The demonstrators were protesting against the military assistance by Saudi Arabia to the ruling Sunni dynasty in Bahrain for the repression of Shiite demonstrations there. Saudi Shiites also feel discriminated and have been demanding equal treatment in employment and social benefits compared to the Sunni majority in the kingdom.